The present invention relates to a gear pump with two meshing gears, in which the trunions of the drive gear are mounted for rotation in the housing of the gear pump, eventually in special bearings, whereas the driven gear has no trunions, but is loosely mounted in the housing and pressed by fluid pressure in such a manner against the drive gear and the housing so that the gears will mesh with each other without play on the flanks of the gear teeth.
In known gear pumps of the aforementioned kind the portion of the housing engaged by the gear teeth extends only over a short part of the circumference of the gears, at the outlet side of the pump which is covered by two side plates. The driven gear is only pressed onto the inner surface of the housing and the drive gear by the fluid pressure acting thereon. Such a pump, in which the driven gear may be mounted in such unstable manner is suitable only for very small feed pressures. Such a pump is, however, completely unsuitable for greater outputs and pressures.